It's a GPS game. You play by walking around and finding collectable seeds. This game is for middle-aged people, you don't need to catch the seeds, just rack up walking time to get them. Some are common and some are rare.

Then you can set up a garden. You plant your seeds by walking around too. There won't be enough space right by your house to plant them all. And some need to grow in special locations. It takes 4-36 hours to grow fruits, vegetable and flowers.

You can walk to the farm stand (located at the nearest library or school) and sell your fruits and veggies. You can buy more advanced seeds. You need to keep walking to various places and checking on your plants.

If you forget to harvest in time someone else might harvest them for you and you only get 1/3 of the proceeds.

Land is limited (though in dense areas there may be multiple instances of the game overlapping)

You can display the flowers on your avatar or build a decorative farm stand

Mostly, it's an excuse to do a bunch of walking.

It would need a lot of art for the various plants and stages of growth.

It's not a joke to code, but I think it far from impossible.

I think it could be very catchy for a particular gaming demographic that mostly gets games made with very little care.